This project is directed to study the interrelationships between the disturbances of systemic and intrarenal hemodynamics and the alterations of kidney function and sodium excretion which occur in cardiovascular diseases such as hypertension and congestive heart failure. The present investigation proposes to investigate the alterations of intrarenal glomerular perfusion (using radioactive microsphere technique) which occur in dogs with acute and chronic partial occlusion of the thoracic vena cava and in dogs with experimental low-output heart failure. Additional experiments are designed to investigate the extent to which the renal nerves, the renin-angiotensin system and the renal prostaglandins modulate renal blood flow and urinary electrolyte excretion in these experimental models of edema formation and also in patients with hypertension and/or oliguric renal failure.